The influence of the cement paste microstructure on corrosion and the adherence of reinforcing bars as a function of the water-cement ratio

Hardened cement paste is a heterogeneous system resulting from the grouping of particles, films, microcrystals and other solid structural elements bounded in a porous mass. The cement paste microstructure must be understood firstly due to its influence on concrete proper-des. The behaviour of concrete greatly depends on the conformation of localised special structures rather than on general structures found in the mass cement paste. The objective of this paper was to study the cement paste microstructure, as a function of the water-cement ratio, in order to interpret the variations of the steel-mortar bond strength and the developing of the corrosion process in steel-mortar specimens kept in tap water and 3 percent sodium chloride solutions for 1 year. A description of the steel-mortar interface was also provided.